Analyte monitoring and management system and methods therefor

ABSTRACT

Method and apparatus for providing multiple data receiver units in a data monitoring and management system such as analyte monitoring system where a first data receiver includes all of the functionalities for the data monitoring and management system receiver unit, and a second data receiver unit is configured with a limited functions to provide application specific convenience to the user or patient is disclosed.

BACKGROUND

Analyte, e.g., glucose monitoring systems including continuous anddiscrete monitoring systems generally include a small, lightweightbattery powered and microprocessor controlled system which is configuredto detect signals proportional to the corresponding measured glucoselevels using an electrometer, and RF signals to transmit the collecteddata. One aspect of certain analyte monitoring systems include atranscutaneous or subcutaneous analyte sensor configuration which is,for example, partially mounted on the skin of a subject whose analytelevel is to be monitored. The sensor cell may use a two orthree-electrode (work, reference and counter electrodes) configurationdriven by a controlled potential (potentiostat) analog circuit connectedthrough a contact system.

The analyte sensor may be configured so that a portion thereof is placedunder the skin of the patient so as to detect the analyte levels of thepatient, and another portion of segment of the analyte sensor that is incommunication with the transmitter unit. The transmitter unit isconfigured to transmit the analyte levels detected by the sensor over awireless communication link such as an RF (radio frequency)communication link to a receiver/monitor unit. The receiver/monitor unitperforms data analysis, among others on the received analyte levels togenerate information pertaining to the monitored analyte levels.

The receiver/monitor units generally include sophisticatedfunctionalities and features, while providing robust data managementsystem, also provide a steep learning curve and challenge to the initialusers of such devices. In addition, due to its sophistication and robustfunctionality, the reduction in the size of the receiver/monitor unitcan be limited. For diabetic children that use the analyte monitoringsystem, for example, having a complex device such as thereceiver/monitor unit may pose a health risk in addition to its intendedbenefit. Indeed, the receiver/monitor unit may be misprogrammed, orotherwise, its settings and/or features modified by the user and thusnot operate properly.

In addition, due to its size, it is cumbersome to engage in physicalactivities such as exercise while carrying the receiver/monitor unit soas to be in signal range with the on-body transmitter unit.

In view of the foregoing, it would be desirable to have a system whichincludes a receiver/monitor unit for use with the data monitoring andmanagement system which is compact in size and that has limited set ofprimary features that is less cumbersome to transport and which is easyto manipulate and use by children, for example.

SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the various embodiments ofthe present invention, there is provided a method and system forproviding a secondary receiver/monitor unit in a data monitoring andmanagement system which is configured for data communication with theprimary receiver/monitor unit, and further, where the secondaryreceiver/monitor unit can replace the functionalities of the primaryreceiver/monitor unit during a predetermined time periods such asexercise periods, sleeping periods, travel periods, or any other periodsduring which access to the full functionality of the primaryreceiver/monitor unit is not needed.

These and other objects, features and advantages of the presentinvention will become more fully apparent from the following detaileddescription of the embodiments, the appended claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a data monitoring and managementsystem for practicing one embodiment of the present invention;

FIG. 2 is a block diagram of the transmitter unit of the data monitoringand management system shown in FIG. 1 in accordance with one embodimentof the present invention;

FIG. 3 is a block diagram of the receiver/monitor unit of the datamonitoring and management system shown in FIG. 1 in accordance with oneembodiment of the present invention;

FIG. 4 is a flowchart illustrating data synchronization procedurebetween the primary receiver unit and the secondary receiver unit of theanalyte monitoring system in accordance with one embodiment of thepresent invention; and

FIG. 5 is a flowchart illustrating data synchronization procedurebetween the primary receiver unit and the secondary receiver unit of theanalyte monitoring system in accordance with another embodiment of thepresent invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a data monitoring and management system such as, forexample, analyte (e.g., glucose) monitoring system 100 in accordancewith one embodiment of the present invention. The subject invention isfurther described primarily with respect to a glucose monitoring systemfor convenience and such description is in no way intended to limit thescope of the invention. It is to be understood that the analytemonitoring system may be configured to monitor a variety of analytes,e.g., lactate, and the like.

Analytes that may be monitored include, for example, acetyl choline,amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase(e.g., CK-MB), creatine, DNA, fructosamine, glucose, glutamine, growthhormones, hormones, ketones, lactate, peroxide, prostate-specificantigen, prothrombin, RNA, thyroid stimulating hormone, and troponin.The concentration of drugs, such as, for example, antibiotics (e.g.,gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs ofabuse, theophylline, and warfarin, may also be monitored.

The analyte monitoring system 100 includes a sensor 101, a transmitterunit 102 coupled to the sensor 101, and a primary receiver unit 104which is configured to communicate with the transmitter unit 102 via acommunication link 103. The primary receiver unit 104 may be furtherconfigured to transmit data to a data processing terminal 105 forevaluating the data received by the primary receiver unit 104. Moreover,the data processing terminal in one embodiment may be configured toreceive data directly from the transmitter unit 102 via a communicationlink 103 which may optionally be configured for bi-directionalcommunication.

Also shown in FIG. 1 is a secondary receiver unit 106 which isoperatively coupled to the communication link and configured to receivedata transmitted from the transmitter unit 102. Moreover, as shown inthe Figure, the secondary receiver unit 106 is configured to communicatewith the primary receiver unit 104 as well as the data processingterminal 105. Indeed, the secondary receiver unit 106 may be configuredfor bi-directional wireless communication with each of the primaryreceiver unit 104 and the data processing terminal 105. As discussed infurther detail below, in one embodiment of the present invention, thesecondary receiver unit 106 may be configured to include a limitednumber of functions and features as compared with the primary receiverunit 104. As such, the secondary receiver unit 106 may be configuredsubstantially in a smaller compact housing or embodied in a device suchas a wrist watch, for example. Alternatively, the secondary receiverunit 106 may be configured with the same or substantially similarfunctionality as the primary receiver unit 104, and may be configured tobe used in conjunction with a docking cradle unit for placement bybedside, for night time monitoring, and/or bi-directional communicationdevice.

Only one sensor 101, transmitter unit 102, communication link 103, anddata processing terminal 105 are shown in the embodiment of the analytemonitoring system 100 illustrated in FIG. 1. However, it will beappreciated by one of ordinary skill in the art that the analytemonitoring system 100 may include one or more sensor 101, transmitterunit 102, communication link 103, and data processing terminal 105.Moreover, within the scope of the present invention, the analytemonitoring system 100 may be a continuous monitoring system, orsemi-continuous, or a discrete monitoring system. In a multi-componentenvironment, each device is configured to be uniquely identified by eachof the other devices in the system so that communication conflict isreadily resolved between the various components within the analytemonitoring system 100.

In one embodiment of the present invention, the sensor 101 is physicallypositioned in or on the body of a user whose analyte level is beingmonitored. The sensor 101 may be configured to continuously sample theanalyte level of the user and convert the sampled analyte level into acorresponding data signal for transmission by the transmitter unit 102.In one embodiment, the transmitter unit 102 is mounted on the sensor 101so that both devices are positioned on the user's body. The transmitterunit 102 performs data processing such as filtering and encoding on datasignals, each of which corresponds to a sampled analyte level of theuser, for transmission to the primary receiver unit 104 via thecommunication link 103.

In one embodiment, the analyte monitoring system 100 is configured as aone-way RF communication path from the transmitter unit 102 to theprimary receiver unit 104. In such embodiment, the transmitter unit 102transmits the sampled data signals received from the sensor 101 withoutacknowledgement from the primary receiver unit 104 that the transmittedsampled data signals have been received. For example, the transmitterunit 102 may be configured to transmit the encoded sampled data signalsat a fixed rate (e.g., at one minute intervals) after the completion ofthe initial power on procedure. Likewise, the primary receiver unit 104may be configured to detect such transmitted encoded sampled datasignals at predetermined time intervals. Alternatively, the analytemonitoring system 100 may be configured with a bi-directional RF (orotherwise) communication between the transmitter unit 102 and theprimary receiver unit 104.

Additionally, in one aspect, the primary receiver unit 104 may includetwo sections. The first section is an analog interface section that isconfigured to communicate with the transmitter unit 102 via thecommunication link 103. In one embodiment, the analog interface sectionmay include an RF receiver and an antenna for receiving and amplifyingthe data signals from the transmitter unit 102, which are thereafter,demodulated with a local oscillator and filtered through a band-passfilter. The second section of the primary receiver unit 104 is a dataprocessing section which is configured to process the data signalsreceived from the transmitter unit 102 such as by performing datadecoding, error detection and correction, data clock generation, anddata bit recovery.

In operation, upon completing the power-on procedure, the primaryreceiver unit 104 is configured to detect the presence of thetransmitter unit 102 within its range based on, for example, thestrength of the detected data signals received from the transmitter unit102 or a predetermined transmitter identification information. Uponsuccessful synchronization with the corresponding transmitter unit 102,the primary receiver unit 104 is configured to begin receiving from thetransmitter unit 102 data signals corresponding to the user's detectedanalyte level. More specifically, the primary receiver unit 104 in oneembodiment is configured to perform synchronized time hopping with thecorresponding synchronized transmitter unit 102 via the communicationlink 103 to obtain the user's detected analyte level.

Referring again to FIG. 1, the data processing terminal 105 may includea personal computer, a portable computer such as a laptop or a handhelddevice (e.g., personal digital assistants (PDAs)), and the like, each ofwhich may be configured for data communication with the receiver via awired or a wireless connection. Additionally, the data processingterminal 105 may further be connected to a data network (not shown) forstoring, retrieving and updating data corresponding to the detectedanalyte level of the user.

Within the scope of the present invention, the data processing terminal105 may include an infusion device such as an insulin infusion pump orthe like, which may be configured to administer insulin to patients, andwhich may be configured to communicate with the receiver unit 104 forreceiving, among others, the measured analyte level. Alternatively, thereceiver unit 104 may be configured to integrate an infusion devicetherein so that the receiver unit 104 is configured to administerinsulin therapy to patients, for example, for administering andmodifying basal profiles, as well as for determining appropriate bolusesfor administration based on, among others, the detected analyte levelsreceived from the transmitter unit 102.

Additionally, the transmitter unit 102, the primary receiver unit 104and the data processing terminal 105 may each be configured forbi-directional wireless communication such that each of the transmitterunit 102, the primary receiver unit 104 and the data processing terminal105 may be configured to communicate (that is, transmit data to andreceive data from) with each other via the wireless communication link103. More specifically, the data processing terminal 105 may in oneembodiment be configured to receive data directly from the transmitterunit 102 via the communication link 103, where the communication link103, as described above, may be configured for bi-directionalcommunication.

In this embodiment, the data processing terminal 105 which may includean insulin pump, may be configured to receive the analyte signals fromthe transmitter unit 102, and thus, incorporate the functions of thereceiver 103 including data processing for managing the patient'sinsulin therapy and analyte monitoring. In one embodiment, thecommunication link 103 may include one or more of an RF communicationprotocol, an infrared communication protocol, a Bluetooth enabledcommunication protocol, an 802.11x wireless communication protocol, oran equivalent wireless communication protocol which would allow secure,wireless communication of several units (for example, per HIPPArequirements) while avoiding potential data collision and interference.

FIG. 2 is a block diagram of the transmitter of the data monitoring anddetection system shown in FIG. 1 in accordance with one embodiment ofthe present invention. Referring to the Figure, the transmitter unit 102in one embodiment includes an analog interface 201 configured tocommunicate with the sensor 101 (FIG. 1), a user input 202, and atemperature detection section 203, each of which is operatively coupledto a transmitter processor 204 such as a central processing unit (CPU).As can be seen from FIG. 2, there are provided four contacts, three ofwhich are electrodes—work electrode (W) 210, guard contact (G) 211,reference electrode (R) 212, and counter electrode (C) 213, eachoperatively coupled to the analog interface 201 of the transmitter unit102 for connection to the sensor unit 201 (FIG. 1). In one embodiment,each of the work electrode (W) 210, guard contact (G) 211, referenceelectrode (R) 212, and counter electrode (C) 213 may be made using aconductive material that is either printed or etched, for example, suchas carbon which may be printed, or metal foil (e.g., gold) which may beetched.

Further shown in FIG. 2 are a transmitter serial communication section205 and an RF transmitter 206, each of which is also operatively coupledto the transmitter processor 204. Moreover, a power supply 207 such as abattery is also provided in the transmitter unit 102 to provide thenecessary power for the transmitter unit 102. Additionally, as can beseen from the Figure, clock 208 is provided to, among others, supplyreal time information to the transmitter processor 204.

In one embodiment, a unidirectional input path is established from thesensor 101 (FIG. 1) and/or manufacturing and testing equipment to theanalog interface 201 of the transmitter unit 102, while a unidirectionaloutput is established from the output of the RF transmitter 206 of thetransmitter unit 102 for transmission to the primary receiver unit 104.In this manner, a data path is shown in FIG. 2 between theaforementioned unidirectional input and output via a dedicated link 209from the analog interface 201 to serial communication section 205,thereafter to the processor 204, and then to the RF transmitter 206. Assuch, in one embodiment, via the data path described above, thetransmitter unit 102 is configured to transmit to the primary receiverunit 104 (FIG. 1), via the communication link 103 (FIG. 1), processedand encoded data signals received from the sensor 101 (FIG. 1).Additionally, the unidirectional communication data path between theanalog interface 201 and the RF transmitter 206 discussed above allowsfor the configuration of the transmitter unit 102 for operation uponcompletion of the manufacturing process as well as for directcommunication for diagnostic and testing purposes.

As discussed above, the transmitter processor 204 is configured totransmit control signals to the various sections of the transmitter unit102 during the operation of the transmitter unit 102. In one embodiment,the transmitter processor 204 also includes a memory (not shown) forstoring data such as the identification information for the transmitterunit 102, as well as the data signals received from the sensor 101. Thestored information may be retrieved and processed for transmission tothe primary receiver unit 104 under the control of the transmitterprocessor 204. Furthermore, the power supply 207 may include acommercially available battery.

The transmitter unit 102 is also configured such that the power supplysection 207 is capable of providing power to the transmitter for aminimum of about three months of continuous operation after having beenstored for about eighteen months in a low-power (non-operating) mode. Inone embodiment, this may be achieved by the transmitter processor 204operating in low power modes in the non-operating state, for example,drawing no more than approximately 1 μA of current. Indeed, in oneembodiment, the final step during the manufacturing process of thetransmitter unit 102 may place the transmitter unit 102 in the lowerpower, non-operating state (i.e., post-manufacture sleep mode). In thismanner, the shelf life of the transmitter unit 102 may be significantlyimproved. Moreover, as shown in FIG. 2, while the power supply unit 207is shown as coupled to the processor 204, and as such, the processor 204is configured to provide control of the power supply unit 207, it shouldbe noted that within the scope of the present invention, the powersupply unit 207 is configured to provide the necessary power to each ofthe components of the transmitter unit 102 shown in FIG. 2.

Referring back to FIG. 2, the power supply section 207 of thetransmitter unit 102 in one embodiment may include a rechargeablebattery unit that may be recharged by a separate power supply rechargingunit (for example, provided in the receiver unit 104) so that thetransmitter unit 102 may be powered for a longer period of usage time.Moreover, in one embodiment, the transmitter unit 102 may be configuredwithout a battery in the power supply section 207, in which case thetransmitter unit 102 may be configured to receive power from an externalpower supply source (for example, a battery) as discussed in furtherdetail below.

Referring yet again to FIG. 2, the temperature detection section 203 ofthe transmitter unit 102 is configured to monitor the temperature of theskin near the sensor insertion site. The temperature reading is used toadjust the analyte readings obtained from the analog interface 201. TheRF transmitter 206 of the transmitter unit 102 may be configured foroperation in the frequency band of 315 MHz to 322 MHz, for example, inthe United States. Further, in one embodiment, the RF transmitter 206 isconfigured to modulate the carrier frequency by performing FrequencyShift Keying and Manchester encoding. In one embodiment, the datatransmission rate is 19,200 symbols per second, with a minimumtransmission range for communication with the primary receiver unit 104.

Referring yet again to FIG. 2, also shown is a leak detection circuit214 coupled to the guard electrode (G) 211 and the processor 204 in thetransmitter unit 102 of the data monitoring and management system 100.The leak detection circuit 214 in accordance with one embodiment of thepresent invention may be configured to detect leakage current in thesensor 101 to determine whether the measured sensor data are corrupt orwhether the measured data from the sensor 101 is accurate.

Additional detailed description of the continuous analyte monitoringsystem, its various components including the functional descriptions ofthe transmitter are provided in U.S. Pat. No. 6,175,752 issued Jan. 16,2001 entitled “Analyte Monitoring Device and Methods of Use”, and inapplication Ser. No. 10/745,878 filed Dec. 26, 2003 entitled “ContinuousGlucose Monitoring System and Methods of Use”, each assigned to theAssignee of the present application, and the disclosures of each ofwhich are incorporated herein by reference for all purposes.

FIG. 3 is a block diagram of the receiver/monitor unit of the datamonitoring and management system shown in FIG. 1 in accordance with oneembodiment of the present invention. Referring to FIG. 3, the primaryreceiver unit 104 includes a blood glucose test strip interface 301, anRF receiver 302, an input 303, a temperature detection section 304, anda clock 305, each of which is operatively coupled to a receiverprocessor 307. As can be further seen from the Figure, the primaryreceiver unit 104 also includes a power supply 306 operatively coupledto a power conversion and monitoring section 308. Further, the powerconversion and monitoring section 308 is also coupled to the receiverprocessor 307. Moreover, also shown are a receiver serial communicationsection 309, and an output 310, each operatively coupled to the receiverprocessor 307.

In one embodiment, the test strip interface 301 includes a glucose leveltesting portion to receive a manual insertion of a glucose test strip,and thereby determine and display the glucose level of the test strip onthe output 310 of the primary receiver unit 104. This manual testing ofglucose can be used to calibrate sensor 101. The RF receiver 302 isconfigured to communicate, via the communication link 103 (FIG. 1) withthe RF transmitter 206 of the transmitter unit 102, to receive encodeddata signals from the transmitter unit 102 for, among others, signalmixing, demodulation, and other data processing. The input 303 of theprimary receiver unit 104 is configured to allow the user to enterinformation into the primary receiver unit 104 as needed. In one aspect,the input 303 may include one or more keys of a keypad, atouch-sensitive screen, or a voice-activated input command unit. Thetemperature detection section 304 is configured to provide temperatureinformation of the primary receiver unit 104 to the receiver processor307, while the clock 305 provides, among others, real time informationto the receiver processor 307.

Each of the various components of the primary receiver unit 104 shown inFIG. 3 is powered by the power supply 306 which, in one embodiment,includes a battery. Furthermore, the power conversion and monitoringsection 308 is configured to monitor the power usage by the variouscomponents in the primary receiver unit 104 for effective powermanagement and to alert the user, for example, in the event of powerusage which renders the primary receiver unit 104 in sub-optimaloperating conditions. An example of such sub-optimal operating conditionmay include, for example, operating the vibration output mode (asdiscussed below) for a period of time thus substantially draining thepower supply 306 while the processor 307 (thus, the primary receiverunit 104) is turned on. Moreover, the power conversion and monitoringsection 308 may additionally be configured to include a reverse polarityprotection circuit such as a field effect transistor (FET) configured asa battery activated switch.

The serial communication section 309 in the primary receiver unit 104 isconfigured to provide a bi-directional communication path from thetesting and/or manufacturing equipment for, among others,initialization, testing, and configuration of the primary receiver unit104. Serial communication section 104 can also be used to upload data toa computer, such as time-stamped blood glucose data. The communicationlink with an external device (not shown) can be made, for example, bycable, infrared (IR) or RF link. The output 310 of the primary receiverunit 104 is configured to provide, among others, a graphical userinterface (GUI) such as a liquid crystal display (LCD) for displayinginformation. Additionally, the output 310 may also include an integratedspeaker for outputting audible signals as well as to provide vibrationoutput as commonly found in handheld electronic devices, such as mobiletelephones presently available. In a further embodiment, the primaryreceiver unit 104 also includes an electro-luminescent lamp configuredto provide backlighting to the output 310 for output visual display indark ambient surroundings.

Referring back to FIG. 3, the primary receiver unit 104 in oneembodiment may also include a storage section such as a programmable,non-volatile memory device as part of the processor 307, or providedseparately in the primary receiver unit 104, operatively coupled to theprocessor 307. The processor 307 is further configured to performManchester decoding as well as error detection and correction upon theencoded data signals received from the transmitter unit 102 via thecommunication link 103.

Referring back to FIGS. 1 and 3, in one embodiment of the presentinvention, the secondary receiver unit 106 may be configuredsubstantially in the manner described in conjunction with FIG. 3.Alternatively, in another embodiment of the present invention, thesecondary receiver unit 106 may be configured to include a limitednumber of functionalities as compared with the primary receiver unit 104described in detail in conjunction with FIG. 3.

For example, in one embodiment of the present invention, the secondaryreceiver unit 106 maybe substantially incorporated into a wrist watchworn by the user of the analyte monitoring system. Accordingly, inaddition to keeping accurate time, the secondary receiver unit 106 isconfigured to receive the transmitted signals from the transmitter unit102 worn by the user. In one embodiment, the wrist watch/secondaryreceiver unit 106 configuration includes a display section that, inaddition to displaying the time and date information, displays themonitored analyte levels substantially in real time received from thetransmitter unit 102. This configuration is also programmable to storethe received analyte data from the transmitter unit 102 which can laterbe transferred to the primary receiver unit 102. Other features of thereceiver unit display such as trend information or graphicalrepresentation of the trend data, may not be displayed in thisconfiguration given the limited display area size on the wrist watch.

In one embodiment, the communication link between the primary receiverunit 104 and the secondary receiver unit 106 may be established usingBluetooth communication protocol, and each device is configured toperiodically transmit data such that the information stored in theprimary receiver unit 104 and the secondary receiver unit 106 aremaintained substantially up to date and in synchronization with eachother. In addition, each of the primary receiver unit 104 and thesecondary receiver unit 106 maybe configured to uniquely identify thetransmitter unit 102 such that both primary receiver unit 104 and thesecondary receiver unit 106 are configured to receive data transmissionfrom the transmitter unit 102 without interruption, and to store thesame in the respective storage sections of the receiver units.

In this manner, in one embodiment of the present invention, the user orpatient may conveniently interchange the use between the primaryreceiver unit 104 and the secondary receiver unit 106 without anyinterruption in the analyte monitoring system 100, and importantly,without losing data transmitted from the transmitter unit 102. Forexample, a diabetic child using the analyte monitoring system 100 maycarry the primary receiver unit 104 in her backpack during the course ofthe day, and wear the secondary receiver unit 106 which is configured asa wrist watch. During the time period when the backpack containing theprimary receiver unit 104 is in close proximity to the transmitter unit102 attached to the body of the diabetic child, the primary receiverunit 104 is configured to receive the transmitted data from thetransmitter unit 102 corresponding to the monitored analyte levels ofthe diabetic child. During recess at school or any other time periodduring which the backpack containing the primary receiver unit 104 isnot in signal range of the transmitter unit 102, the secondary receiverunit 106 is configured to receive the signals from the transmitter unit104. Periodically during the day or at a preprogrammed time during a 24hour period, the primary receiver unit 104 may be configured tosynchronize with the secondary receiver unit 106 such that all of thetransmitted signals from the transmitter unit 102 are stored in theprimary receiver unit 104.

Such multiple receiver unit implementation of the analyte monitoringsystem may be additionally beneficial in other circumstances. Forexample, the secondary receiver unit 106 may be used during the timeperiod that the user or patient is engaged in physical activities suchas sports or other types of activities where carrying an electronicdevice such as the primary receiver unit 104 may be cumbersome.

In addition, the secondary receiver unit 106 may be configured tooperate in a low power transmission state such as that complying withClass B transmission regulated by the Federal Aviation Authority (FAA)which mandate electronic transmission devices to be turned off duringairplane take off and landing procedures. In such cases, the primaryreceiver unit 104 may be powered down completely while the Class-Bcompliant secondary receiver unit 106 maybe configured to continuereceiving the signals from the transmitter unit 102. Thereafter, at alater time period when the primary receiver unit 104 may be turned on,the primary receiver unit 104 is configured to synchronize data with thesecondary receiver unit 106 so that the transmitted signals from thetransmitter unit 102 during the time that the primary receiver unit 104was turned off can be captured and stored in the primary receiver unit104.

FIG. 4 is a flowchart illustrating data synchronization procedurebetween the primary receiver unit and the secondary receiver unit of theanalyte monitoring system in accordance with one embodiment of thepresent invention. Referring to FIG. 4, at step 410 in one embodiment ofthe present invention, the secondary receiver unit 106 (FIG. 1) isconfigured to receive and store the signals received from thetransmitter unit 102 that are associated with the monitored analytelevels. Thereafter at step 420, the secondary receiver unit 106determined whether the primary receiver unit 104 is back in the power onstate. In one embodiment, the primary receiver unit 104 may beconfigured to broadcast a power on state signal as soon as it is poweredon. Alternatively, in another embodiment, the secondary receiver unit106 is configured to periodically transmit a signal to the primaryreceiver unit 104, and when a return acknowledgement signal is receivedby the secondary receiver unit 106 as originating from the primaryreceiver unit 104, it is determined that the primary receiver unit 104is in the powered on state.

Referring back to FIG. 4, if it is determined at step 420 that theprimary receiver unit 104 is not in the power on state, then thesecondary receiver unit 106 returns to step 410 where the transmitterunit 102 signals are continuously received and stored. If however it isdetermined at step 420 that the primary receiver unit 104 is in thepower on state, then at step 430, the secondary receiver unit 106 isconfigured to retrieve the stored data received from the transmitterunit 102, and at step 440, the secondary receiver unit 106 is configuredto transmit the retrieved data corresponding to data received from thetransmitter unit 102 to the primary receiver unit 104. Thereafter,optionally, the secondary receiver unit 106 may be configured to enter apowered down or hibernate mode to conserve its power supply. In thehibernate mode, the secondary receiver unit 106 may be configured to notaccept data transmitted from the transmitter unit 102.

In an alternate embodiment, the secondary receiver unit 106 may beconfigured to continue to receive the transmitted data from thetransmitter unit 102 even when the primary receiver unit 104 is in thepower on state and receiving data from the transmitter unit 102. In thismanner, transmitter unit 102 data redundancy may be achieved.

FIG. 5 is a flowchart illustrating data synchronization procedurebetween the primary receiver unit and the secondary receiver unit of theanalyte monitoring system in accordance with another embodiment of thepresent invention. Referring to FIG. 5, at step 510, the primaryreceiver unit 104 (FIG. 1) entered the power on state by, for example,the user or patient powering on the primary receiver unit 104.Thereafter at step 520, the primary receiver unit 520 is configured toretrieve the time information associated with the power off stateduration. For example, in one embodiment, the primary receiver unit 104is configured to retrieve the time stamp information (as maybe providedby its internal clock 305 (FIG. 3) of the beginning of the power offstate, and the time stamp information of the beginning of the power onstate.

Referring to FIG. 5, the retrieved time information associated with thepower off duration is transmitted to the secondary receiver unit 106 atstep 530. Thereafter, at step 540, the primary receiver unit 104 isconfigured to receive transmitter unit 102 data from the secondaryreceiver unit 104 that correspond to the time information associatedwith the power off duration. That is, since during the power off statethe primary receiver unit 104 did not receive any data from thetransmitter unit 102 which are associated with the monitored analytelevel, the primary receiver unit 104 may be configured in one embodimentto receive this data from the secondary receiver unit 106.

In addition, within the scope of the present invention, the primaryreceiver unit 104 and the secondary receiver unit 106 may be configuredas a bedside monitor system where, the secondary receiver unit 106 (orinterchangeably the primary receiver unit 104) may be placed at or nearthe bedside of the child or patient wearing the transmitter unit 102.The primary receiver unit 104 (or interchangeably the secondary receiverunit 106) may be placed at another location within the house (orhospital or any other location within communication range with thesecondary receiver unit 106. In this manner, even though the RFcommunication link 103 between the transmitter unit 102 and the remotelylocated primary receiver unit 104 may not be enabled due to distance,the secondary receiver unit 106 which is in signal communication withthe transmitter unit 102 may be configured as a relay device toretransmit the received transmitter unit 102 signals to the primaryreceiver unit 104. In this manner, parents of diabetic children wearinga transmitter unit 102 to monitor the children's glucose levels, orpatients in hospitals may conveniently and remotely monitor the analytelevels substantially in real time.

Accordingly, a system for providing analyte monitoring in one embodimentof the present invention includes a sensor configured for subcutaneousplacement for detecting a plurality of analyte levels, a transmitterunit configured for electrical communication with the sensor; thetransmitter unit configured to transmit a plurality of signals eachassociated with a respective one or more of the detected plurality ofanalyte levels, a first receiver unit configured to receive a firstportion of the transmitted plurality of signals from the transmitterunit, a second receiver unit configured to receive a second portion ofthe transmitted signals from the transmitter unit.

In one embodiment, each of the plurality of signals transmitted by thetransmitter unit maybe associated with a corresponding detection timeinformation, where each detection time information may substantiallycorrespond to the detection time of the corresponding associated analytelevel by the sensor.

The second receiver unit maybe configured to transmit the receivedsecond portion of the signals to the first receiver unit, where thefirst portion of the plurality of signals and the second portion of theplurality of signals may be substantially non-overlapping.

Further, the first receiver unit may include a storage unit for storingthe first and second portions of the plurality of the signals.

In addition, the first receiver unit may include an output unit foroutputting one or more of a visual indication, an audible indication ora vibratory indication associated with the received one or more of theplurality of signals.

In a further aspect, the second receiver unit may include a housingsubstantially configured as one of a wrist watch, a bed side monitorunit, a two way radio communication unit, a mobile telephone, a pager,or a personal digital assistant.

The first receiver unit and the second receiver unit in yet anotheraspect may be configured to communicate over a communication link whichmay include one or more of an infrared communication link, an RFcommunication link, a Bluetooth communication link, or a cableconnection.

In yet another aspect, each of the first and second receiver units maybe configured for bi-directional communication.

A method of analyte monitoring in accordance with another embodiment ofthe present invention includes transmitting a plurality of signalsassociated with detected analyte levels, receiving a first portion ofthe plurality of signals at a first remote location, receiving a secondportion of the plurality of signals at a second remote location, whereinthe first and second portions of the plurality of signals aresubstantially non-overlapping.

The method may further include transmitting the second portion of theplurality of signals from the second remote location to the first remotelocation.

In another aspect, the method may also include one or more steps ofstoring the plurality of signals, or displaying at least a portion ofthe plurality of signals.

A method of analyte monitoring in accordance with still anotherembodiment of the present invention includes receiving one or moresignals associated with a respective one or more analyte levels beingmonitored, storing the received one or more signals, detecting an activestate of a receiver unit, and transmitting the stored one or moresignals to the receiver unit.

In another aspect, the method may also include the steps of detectingthe one or more analyte levels, and transmitting the one or more signalseach corresponding to the detected one or more analyte levelssubstantially in real time.

A method of analyte monitoring in still yet another embodiment of thepresent invention includes retrieving a time information associated withan inactive state, transmitting the retrieved time information, andreceiving one or more signals each associated with a monitored analytelevel corresponding to the time information.

The time information may include a beginning time and an end time of theinactive state.

In a further aspect, the method may also include the storing thereceived one or more signals.

Various other modifications and alterations in the structure and methodof operation of this invention will be apparent to those skilled in theart without departing from the scope and spirit of the invention.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments. It isintended that the following claims define the scope of the presentinvention and that structures and methods within the scope of theseclaims and their equivalents be covered thereby.

1. A system for providing analyte monitoring, comprising: a sensorconfigured for subcutaneous placement for detecting a plurality ofanalyte levels; a transmitter unit configured for electricalcommunication with the sensor; the transmitter unit configured totransmit a plurality of signals each associated with a respective one ormore of the detected plurality of analyte levels; a first receiver unitconfigured to receive a first portion of the transmitted plurality ofsignals from the transmitter unit; and a second receiver unit configuredto receive a second portion of the transmitted signals from thetransmitter unit at least during an inactive state of the first receiverunit; wherein the first receiver unit is further configured to providetime information associated with the inactive state.
 2. The system ofclaim 1 wherein each of the plurality of signals transmitted by thetransmitter unit is associated with a corresponding detection timeinformation.
 3. The system of claim 2 wherein each detection timeinformation substantially corresponds to the detection time of thecorresponding associated analyte level by the sensor.
 4. The system ofclaim 1 wherein the second receiver unit is configured to transmit thereceived second portion of the signals to the first receiver unit. 5.The system of claim 4 wherein the first portion of the plurality ofsignals and the second portion of the plurality of signals aresubstantially non-overlapping.
 6. The system of claim 4 wherein thefirst receiver unit includes a storage unit for storing the first andsecond portions of the plurality of the signals.
 7. The system of claim1 wherein the first receiver unit includes an output unit for outputtingone or more of a visual indication, an audible indication or a vibratoryindication associated with the received one or more of the plurality ofsignals.
 8. The system of claim 1 wherein the second receiver unitincludes a housing substantially configured as one of a wrist watch, abed side monitor unit, a two way radio communication unit, a mobiletelephone, a pager, or a personal digital assistant.
 9. The system ofclaim 1 wherein the first receiver unit and the second receiver unit areconfigured to communicate over a communication link.
 10. The system ofclaim 9 wherein the communication link includes one or more of aninfrared communication link, an RF communication link, or a cableconnection.
 11. The system of claim 9 wherein each of the first andsecond receiver units are configured for bi-directional communication.12. The system of claim 1 wherein the time information includes abeginning time and an end time of the inactive state.
 13. A method ofanalyte monitoring, comprising: transmitting a plurality of signalsassociated with detected analyte levels; receiving a first portion ofthe plurality of signals at a first remote location; receiving a secondportion of the plurality of signals at a second remote location at leastduring an inactive state of the first remote location; and storing timeinformation associated with the inactive state at the first remotelocation.
 14. The method of claim 13 further including the step oftransmitting the second portion of the plurality of signals from thesecond remote location to the first remote location.
 15. The method ofclaim 13 further including the step of storing the plurality of signals.16. The method of claim 13 further including the step of displaying atleast a portion of the plurality of signals.
 17. The method of claim 13wherein the time information includes a beginning time and an end timeof the inactive state.
 18. The method of claim 13 wherein the first andsecond portions of the plurality of signals are substantiallynon-overlapping.
 19. A method of analyte monitoring, comprising:retrieving a time information associated with an inactive state of aprimary receiver unit; transmitting the retrieved time information fromthe primary receiver unit to a secondary receiver unit; and receivingone or more signals from the secondary receiver unit with the primaryreceiver unit, each signal associated with a monitored analyte levelcorresponding to the time information.
 20. The method of claim 19wherein the time information includes a beginning time and an end timeof the inactive state.
 21. The method of claim 19 further including thestep of storing the received one or more signals in the primary receiverunit.